Devices permitting the sequential display of a plurality of coded images by relative movement of an image member relative to a shutter member have been known for many years. Typically, the image member has a plurality of interposed coded images thereon while the shutter member has a plurality of shutter elements that are separated by a plurality of viewing elements. The shutter elements perform the dual functions of selectively blocking from view all but one of the interposed coded images while bridging the gaps between the coded strips to form what can be termed an active image. The shutter elements uncode the active image of the coded images, and the active image appears to be complete.
When the image member and the shutter member undergo relative movement by a predetermined amount, the strips of the previously active image are concealed and the next succeeding coded image assumes the fleeting position as an active image. This procedure will continue through a cycle consisting of all coded images that are disposed on the image member. Once that cycle is complete, the first coded image will again appear to start a new, identical cycle.
The number of unique coded images is mathematically limited by the width of the shutter element relative to the width of the strips that form the coded images. Stated more particularly, the number of coded images cannot exceed one plus the result of the width of each shutter element divided by the width of each coded image strip. The ability to display images with clarity and resolution is dependent not only on the number of discrete images that can be displayed but also on the ability of the device to obtain precise registration and alignment between the coded images and the shutter elements and to maintain that precise registration during relative movement within the device.
Just as critical to the performance of such display devices is the ability of the device to achieve and maintain close contact between the shutter elements and the coded images over their entire display surfaces. Lack of complete contact between the shutter elements and the coded images creates thin air pockets between the layers thereby creating undesirable shadows that diminish the observer's ability to perceive the display image. Incomplete contact also results in an undesirable parallax viewing conflict where multiple images can be partially or completely perceived due to the ability of the observer to see around and, therefore, behind the shutter elements.
Where complete contact between the shutter elements and the coded images is not achieved, the intended animation effect will be frustrated and the designer may be forced to compensate by implementing a design with sufficiently few animation phases to eliminate the viewing conflicts and other resulting disadvantages. Conversely, where better contact can be achieved, more and clearer phases of animation are possible thereby enabling more advanced and intricate animation sequences.
In one type of animation device, a coded image member is rotatable, often manually, relative to a shutter member to achieve animation. Such optically animated display devices often cause the coded image member, which can be disk shaped, to be rotatable about a common axis in relation to the shutter member, which also can be disk shaped. In such devices, the two members have sometimes been loosely riveted or otherwise coupled together. The shutter member typically has opaque, radiating shutter elements while the coded image member, often the bottom of the two, typically has radiating coded images.
While such devices have been in existence for over a century, their full potential has yet to be realized for a number of reasons. For example, a rarely recognized yet essential requirement to achieve optimal results in such devices is that the shutter member and the coded image member must be held in complete contact against one another at all times, including before, during, and after rotation. Prior art devices have failed to do so in reliance on the assumption that the shutter and image members are both perfectly flat, which is normally not the case. Therefore, unless the shutter member is completely pressed against the image member, the shutter member generally will not conform to a surface on which it lies. With this, random areas of non-contact are created that compromise the optimal performance of the device in at least two ways.
First, areas of non-contact cause unwanted shadows to be cast by the upper shutter elements on the bottom coded image elements. This obscures the animated image, which even under the best of conditions is already perceived as dark since the shutter elements create a dark veil of necessary stripes over the depicted image. The resulting shadows create mottled patches of darkness that compromise the clear perception of the intended animated image.
Second, the areas of non-contact permit the observer to perceive portions of coded image elements that are intended to be hidden beneath shutter elements. With this, the successful incorporation of more than two or three phases of animation, which would require the use of finer and finer shutter elements and radiating coded images, is made functionally impossible since the slightest lack of contact reveals one or more other phases of animation to the observer at the wrong time. Since the observer typically sees with binocular vision, there is an unintentional perception of confusing double, triple, or even quadruple images thereby distracting from the intended animation. To date, these undesirable effects deriving from insufficient contact between the shutter member and the image member have limited the appeal of the devices to the general public and have, therefore, prevented their widespread commercial success.
Advantageously, the present inventor has appreciated that achieving optimal functional performance and, ideally, realizing full commercial success, demands that the shutter member and the image member be maintained in sufficient compression to achieve and maintain complete contact before, during, and after rotation. It is further recognized that the image and shutter members must simultaneously be readily movable, in this case rotatable, relative to one another.
The present inventor has demonstrated the functional improvements derived from imposing full contact between relatively slidable elements of optically animated devices in, for example, U.S. Pat. No. 5,901,484, entitled “Manually Operated Moveable Display Device,” and in U.S. Provisional Patent App. No. 60/534,894, entitled “Moveable Animated Display Device.” Each disclosure is incorporated herein by reference. Embodiments of each invention have achieved commercial success thereby attesting to the merit of this heretofore neglected, yet critical, improvement in the art and the need for an invention that can provide such improvements in relation to rotatable display devices.